Hybrid vehicles and electric vehicles, which are recently under further development, are equipped with secondary batteries (batteries) such as nickel-hydride batteries and lithium-ion batteries.
Such batteries have optimum usage temperature ranges and it is known that battery power decreases under a low-temperature condition of, for example, 0° C. or below.
In order to deal with such a problem, Patent Document 1 discloses an air conditioning apparatus 100 for electric vehicles (see FIG. 18) capable of cooling or heating a battery 151 in a battery frame 150 utilizing air for car cabin air-conditioning, in which the air conditioning apparatus 100 includes an air box 101, a blower fan 102 serving as an air blower, a cooling unit 103 capable of cooling air from the blower fan 102, a sub-condenser 104 capable of heating air which has passed through the cooling unit 103, and an indoor duct 105 that introduces air which has passed through the sub-condenser 104 into the car cabin, wherein a battery duct 106 branches from the indoor duct 105 to guide air to the battery frame 150, and wherein a battery door 107 is provided at a location where the indoor duct 105 and the battery duct 106 branch, the battery door 107 being capable of switching air, which has passed through the sub-condenser 104, to an indoor duct 105-side or to a battery duct 106-side, and being capable of adjusting an opening of the switching.
Patent Document 2 discloses an electric vehicle-mounted battery temperature regulation apparatus that is configured to cool or warm a vehicle propulsion battery accommodated in a battery case by introducing air used for car cabin air-conditioning into the battery case via an introducing channel. Patent Document 3 discloses covering a battery with a heat insulating material and, in addition, using a heating device such as an electric heater, in order to prevent the temperature of the battery from decreasing in a cold climate or in a cold region. Further, Patent Document 4 discloses a secondary battery module including a plurality of unit batteries, a partition disposed between the unit batteries adjacent to each other, a housing in which the unit batteries and the partition are installed and provided with an inlet and an outlet through which a heat transfer medium flows, and a PTC heater provided between the partition and the unit battery.